REGION OF THE CAROTID ARTERIES. 



83 



traction. That portion of the cervical aponeurosis which 

 forms the anterior layer of the sheath of the muscle is 

 next seen, attached above to the angle of the jaw (almost 

 appearing to divert the anterior border of the muscle 



Diagram of the parts seen in a horizontal section through the sixth cervical 

 vertebra. A. Body of sixth cervical vertebra. B. Spinal cord. c. Thyroid car- 

 tilage. r>. Cricoid cartilage. E. Sterno-hyoid muscle. F. Omo-hyoid. G. Com- 

 mon carotid artery. H. Internal jugular vein. K. Platysma. L. Sterno-thyroid. 

 M. Opening of larynx. N. Inferior constrictor, o. Summit of lateral lobe of 

 thyroid body. p. (Esophagus. Q. Thyro-arytenoid muscle. R. Spinalis colli. 

 v. Trapezius. x. Splenius. Y. Complexus. d. External jugular vein. 6. Vagus 

 nerve, e. Longus colli. /. Scalenus anticus. m. Sterno-cleido-mastoid. n. 

 Vertebral vessels, p. Sympathetic, s. Descendens noni. 



from the straight line), and below to the clavicle, and 

 to the corresponding facial sheath of the opposite mus- 

 cle; and after completely inclosing the muscle at its 

 posterior border, it becomes continuous with the apon- 

 eurosis of the neck. 



The sterno-cleido-mastoid is perforated on its under 

 surface, near the centre, by the spinal accessory nerve, 



